POW questionaires were filled in by returning POW's. These are held at the National Archives at Kew in the WO 344 series. You will need to visit Kew and see if one exists for Haddleton. They will not search for you and I understand it might take a while as they are in no particular order.
I presume you know he was held at Stalag Luft 6 Heydekrug for most of his period of captivity
Haddleton is not a very common name (only one POW by that name from the Air Forces). The Service Number for your man is R/94765 and his christian names are William Desmond. At the time of his capture his family were living in Climax, Saskatchewan. A search of the Canadian Yellow pages brings up one entry
This may or may not be the person you are seeking but it could be a start.
You could consider putting an appeal in the appropriate provincial newspaper covering Climax
Check out this link